1. Field of the Invention
The present invention relates generally to electrical wiring device assemblies, and particularly to electrical wiring device assemblies with wall plates.
2. Technical Background
When an electrical wiring device is installed in new construction, a wall box is attached to one of the framing studs, and sheetrock or some other material, is placed over the framing studs with a wall box opening formed therein. (In an old-work installation, an opening is formed in an existing wall surface and the wall box is attached to the wall surface). Once the walls are “sheet rocked” and mudded, an electrician connects the terminals of the electrical wiring device to their respective hot and neutral conductors, and attaches the wiring device to the wall box. (Those skilled in the art will appreciate that the term electrical wiring device refers to, but is not limited to, electrical switches, outlet receptacles, protective devices (e.g., GFCIs, AFCIs, etc.), lighting dimmers, fan or motor speed control devices, and etc.).
After the electrical wiring device is installed, a wall plate is typically placed over the installed electrical wiring device to complete the enclosure, i.e., to prevent the building occupant from having access to the interior of the wall box. In other words, the wall plate functions as a protective cover for the wall box installation by preventing access to the electrical wires in the interior of the electrical box. Moreover, the wall plate has an aesthetic function because it hides the wall opening, the electrical wiring, the wall box and the electrical wiring device ground straps and provides a finished look. While the typical wall plate may be suitable from a protective standpoint (i.e., it completes the enclosure), it usually falls short aesthetically.
Referring to FIG. 1A, an example of a conventional “No. 8” wall plate 1 is shown. This type of wall plate is, of course, configured to complete the enclosure for a standard outlet receptacle having top and bottom receptacles. The wall plate includes a wall portion 1-1 that abuts the wall surface if the wall surface is relatively flat. If the wall surface is not flat, the wall portion 1-1 may draw attention to the uneven nature of the wall since gaps will become apparent between the wall plate and recessed regions of the wall surface. In FIG. 1A, the wall plate 1 is comprised of approximately 21 separate substantially planar facets 1-2. Moreover, plate 1 also includes a miter joint 1-3 at each corner thereof. Each facet is substantially planar and thus exhibits a specular reflection; i.e., light originating from a single incoming direction is reflected from the planar surface so that the outgoing light is directed toward a single outbound direction. Since there are about 21 facets, there will be 21 reflected light beams directed outwardly toward the user. Thus, everywhere a tangent surface meets a substantially planar surface; the various reflections can produce a “house of mirrors” effect, wherein each surface or pane reflects a different image outwardly in a different direction. Of course, the glare issue can be overcome by replacing the smooth glossy plastic surface of the typical wall plate with other finish materials that do not reflect light. The drawback with this approach is that many of these non-reflective materials, e.g., fabric, etc., collect dirt and grime over time.
In reference to FIG. 1B, a conventional wall plate 2 having a No. 26 opening is shown. Wall plate 2 may be used to complete the enclosure for any type of electrical wiring devices that can fit within the No. 26 opening. All told, this design includes about twenty-five (25) substantially planar surfaces, each potentially being a source of specular reflection. As before, the glare issue can be overcome by replacing the smooth glossy plastic surface of the typical wall plate with other finish materials that do not reflect light. The drawback with this approach is that many of these non reflective materials collect dirt and grime over time. The wall plate 2 also includes a wall portion 2-1 that abuts the wall surface if the wall surface is relatively flat. Once again, if the wall surface is not flat, the wall portion 2-1 may draw attention to the uneven nature of the wall.
In reference to FIG. 1C, another conventional wall plate 3 having a modified No. 26 opening is shown. The wall plate includes a wall portion 3-1 that abuts the wall surface if the wall surface is relatively flat. (As before, if the wall surface is not flat, the wall portion 3-1 may draw attention to the uneven nature of the wall). The cross-sectional profiles of the members (3-4, 3-5) of the wall plate 3 are characterized by splines (a piece wise function). Specifically, each cross-sectional profile is subdivided into parallel segments that have approximately the same width (about 0.01 inches); the height of these segments is typically different. The vertical spline 3-4 defines a surface having a positive first differential, i.e., each segment has increasing height relative to the one before and the rate at which the surface height increases is not constant. The vertical spline 3-4 also defines a surface having a negative second differential since height differences of the segments decrease from left to right. The difference between the first segment height and second segment height is larger than the difference between the second and the third segment heights, etc. The segments of the spline are therefore not connected by a single arc. The spline of the horizontal members 3-5 may be, and usually is, different than the spline of the vertical member 3-4. When the horizontal splines and the vertical splines meet at the corners of the wall plate, they form a miter joint 3-3. When the spline changes its direction, which in this case is every segment (e.g., about 0.01 inches), the light defuses at a different rate making the gradient of the reflected light (or shadow as the case may be) inconsistent and visually unappealing.
As shown in FIG. 1C, the surface of the splined wall plate 3 may show the spline segmentations as an artifact of the injection molding process; as before, reflected light will be reflected in various directions. Moreover, the discontinuity of the miter joint is also visible when light shines on the surface of plate 3. Some users may see the reflected light as glare or “hard on the eye,” and thus find them aesthetically displeasing. Once again, the glare issue can be overcome by replacing the smooth glossy plastic surface of the wall plate with non-reflective finish materials; the drawback with this approach is that many of these non-reflective materials collect dirt and grime, and can look dingy over time. Another drawback of this design relates to the wall portion 3-1. Once again, the wall portion 3-1 is configured to abut the wall surface of the installation. As before, if the wall surface is not flat, the bottom of the wall portion 3-1 may draw attention to the uneven nature of the wall while the curvilinear top edge tends to cast curvilinear shadows against the wall. These shadows tend to make the wall plate appear relatively thick or “heavy” looking. Some users find this thickness or heaviness to be aesthetically displeasing.
Some electrical wiring device installations may include multiple wiring devices positioned side by side in a common multi-gang box. The multi-gang box includes several pairs of mounting tabs, each pair being separated from an adjacent pair of mounting tabs by a standard distance, such as 1.812 inches. This standard distance is commonly referred to as a “single-gang width.” Of course, each pair of mounting tabs includes a fastener aperture disposed in the top wall of the box and a corresponding fastener aperture disposed in the bottom wall of the box. The centerline passing through the top and bottom fastener holes of each pair is substantially parallel to the side walls of the box. Each device mounted in the multi-gang box is fastened to the top and bottom holes by inserting a fastener screw therein. This gives rise to the problem that the wiring devices are not aligned to each other by the box.
In one approach, the installer may attempt to install one individual wall plate over each device (one plate per gang). The installer then tries to attach the individual wall plates on the box such that they abut each other edge-to-edge. However, if the individual dimmers are not perfectly aligned with each other, the wall plates will not be perfectly aligned either. The wall plates will exhibit a stepped appearance that is both unacceptable and undesirable because the edges of the individual wall plates tend to look rough and non-uniform. In another approach that has been considered, designers avoid the use of individual plates by ordering a custom plate to fit over the entire ensemble of electrical wiring devices. The drawback to this approach relates to the cost and lead time of having a custom wall plate manufactured.
What is needed is a wall plate that obviates or overcomes the drawbacks articulated above. Specifically, an electrical wiring assembly is needed that features a wall plate that has a single surface that reflects light in a uniform and diffuse way so that glare is substantially eliminated and a more aesthetically pleasing presentation is achieved. Moreover, a wall plate is needed that minimizes the perceived thickness of the wall plate, and tends to hide uneven wall surfaces. All of the desirable features articulated above are also needed in a multi-gang wall plate.